Crop culture with 4h-1,2,4-triazoles

ABSTRACT

THE PRESENT INVENTION RELATES TO CROP CULTURE AND IS PARTICULARLY CONCERNED WITH PRACTICES FOR CONSERVING SOIL NITROGEN AND FOR SUPPLYING THE REQUIREMENTS FOR PLANT NUTRITION. THESE PRACTICES INVOLVE THE EMPLOYMENT, AS ACTIVE AGENT, OF 4-AMINO-4H-1,2,4-TRIAZOLE, 3,4-DIAMINO4H-1,2,4-TRIAZOLE OR A MINERAL ACID ADDITION SALT OF THESE COMPOUNDS. USEFUL COMPOSITIONS EMPLOYING SUCH COMPOUNDS ARE ALSO DISCLOSED. TYPICAL COMPOSITIONS COMPRISE A REDUCED NITROGEN FERTILIZER AND A TRIAZOLE COMPOUND.

Uni-tec l States Patent ()flice 3,697,244 Patented Oct. 10, 1972 3,697,244 CROP CULTURE WITH 4H-1,2,4-TRIAZOLES Henry H. Scott, Walnut Creek, Califi, assignor to The Dow Chemical Company, Midland, Mich. No Drawing. Filed Oct. 15, 1968, Ser. No. 767,851

Int. Cl. C05g 3/08 U.S. Cl. 71-1 4 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION The nature of the agricultural problem for which the present invention constitutes a remedy has previously been discussed in the prior art: see, for example, the introduction to U.S. Pat. 3,135,594, dated June 2, 1964.

SUMMARY OF THE INVENTION The present invention is directed to a method and composition useful therewith in crop culture, and is particularly concerned with new agronomical practices and compositions for conserving nitrogen in soil by suppressing the nitrification of ammonium nitrogen therein. The active agent of the compositions employed in such methods is 4- amino-4H-1,2,4-triazole, 3,4-diamino-4H-1,2,4-triazole or salts of one or the other of these compounds with mineral acids including hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, nitric acid and phosphoric acid. Typical salt compounds are 4-amino-4H-1,2,4-triazolechydrobromide, 4 amino 4H-1,2,4-triazole:hydroiodide, 4-amino-4H-1,2,4-triazole:hydrochloride, 4-amino- 4H 1,2,4-triazolezsulfate, 3,4-diamino-4H-1,2,4-triazole: hydrochloride, 3,4 diamino 4H 1,2,4 triazole: nitrate, 3,4-diamino-4H-1,2,4-triazolezphosphate and 3,4- diamino-4H-1,2,4-triazole:sulfate. For convenience of description, these active compounds will be referred to herein as 4H-1,2,4-triazoles or simply as triazoles.

The method of the present invention comprises impregnating a plant growth medium with the triazole compound either with or without an adjuvant. The triazole compound, when present in effective amounts, acts to suppress nitrification of ammonium nitrogen in the soil to nitrate nitrogen, thereby preventing rapid loss of ammonium nitrogen from the soil.

In the practice of the present invention, an effective nitrification-inhibiting amount of a triazole compound, as set forth hereinbefore, is incorporated into soil or other growth medium.

Ordinarily the present invention is carried out either by distributing the triazole compound in an unmodified form through the soil or other growth medium or distributing the compound in such media as a constituent in liquid or finely divided solid compositions. In the latter practice, the triazole compound can be modified with one or more additaments or soil treating adjuvants including water, petroleumdistillates or other liquid carriers, surface-active dispersing agents, inert finely divided solids and fertilizers such as reduced nitrogen fertilizers. Preferred adjuvants are surface-active-dispersing agents, inert finely divided solids, and, especially, reduced nitrogen fertilizers; these adjuvants cooperate with the triazole compound so as to facilitate the practice of the present invention and to obtain an improved results. Depending upon the concentration of the triazole compound, augmented compositions can be distributed in the soil without further modification or can be considered as concentrates and subsequently diluted with additional inert carrier to produce the ultimate treating composition. The required amount of the triazole compound can be supplied to growth media in from 1 to 50 gallons of organic solvent carrier, in from 5 to 27,000 or more gallons of aqueous carrier or in from 20 to 2,000 pounds of solid carrier per acre treated. When an organic solvent carrier is employed, it can be further dispersed in the above volume of aqueous liquid carrier.

The provision of an effective, nitrification-inhibiting, dosage of the triazole compound in the soil or growth medium is essential for the practice of the present invention. In general, good results are obtained when the growth medium is impregnated with the triazole compound in the amount of from about 0.01 part to about 4000 parts or more by weight per million parts by weight of growth medium. (Hereinafter, the term p.p.m. is employed as customary to designate parts per million.) The preferred amounts to be employed are dependent upon the particular situation. Thus, in determining the amount to be employed, consideration is made not only of the treatment need, i.e., soil pH, temperature, soil type, etc., but also of the mode of application to soil. When the triazole compound is to be applied in a broadcast application, the amount in p.p.m. may frequently be less than in row or band application where for a substantial depth and width within the vicinity of application there can be a very high concentration of the triazole compound. When application is made near the root zone of growing plants or when application is made immediately prior to seeding or transplanting, the amounts supplied are frequently at a lower rate than when application is made at the end of the growing season to prepare the soil for the following season. By dispersing very large dosages in growth media, a prolonged inhibition of nitrification can be obtained over a period of many months. The concentration of the active triazole compound is eventually reduced to a minimum by decomposition in the soil.

In one specific embodiment for carrying out the present invention, the triazole compound is distributed throughout the growth media in a broadcast application such as by spraying, dusting, distributing in irrigation water, etc. In such application, the triazole compound is supplied in amounts sufficient to permeate the growing area of soil with an amount of from about 0.1 to about 1000 p.p.m., and preferably, from about 2 to about 250 p.p.m. In field administration, the triazole compound can be distributed in the soil in the amount of at least 0.2 pound per acre and through such cross-section of the soil as to provide for the presence therein of an eifective concentration of the agent. It is usually preferred that the triazole compound be distributed to a depth of at least two inches below the soil surface and at a dosage of at least 0.1 pound per acre inch of soil.

In another embodiment for carrying out the present invention, the i triazole compound is administered to growth medium in ,a band or row application. In such application, administrationis made with or without carrier in amounts sufficient to supply to soil or growth medium a concentration of the triazole compound which can be as high as 4000 p.p.m. or more. After administration with or without disking or dragging, subsequent irrigation or rainfall distributes the triazole compound throughout the growth medium.

In one embodiment of the present invention, the triazole compound is distributed throughout the growth media prior toseeding or transplanting the desired crop plant.

In another embodiment, the soil in the root zone of growing plants is treated with the triazole compound in an amount effective to inhibit nitrification but sublethal to plant growth. In such operations, the compounds should be supplied in the soil in amounts which have preferred upper limits at about 50 p.p.m. By following such prac-v tice, no adverse effect is exerted by the triazole compound upon growth of seeds or plants. Oftentimes it is desirable to treat the soil adjacent to plants, and this procedure may be, carried out conveniently in side-dressing operations.

In a further embodiment, soil can be treated with the products following harvest or after fallowing to prevent rapid loss of ammonium nitrogen and to build upthe ammoniumv nitrogen formed by conversion of organic nitrogen compounds. Such practice conserves the soil nitrogen for the following growing season. In such application the upper limit is primarily an economic consideration.

In an additional embodiment, the soil is treated with the triazole compound in conjunction with the application of reduced nitrogen fertilizers. The treatment with the triazole compound can be carried out prior, to subsequent to or simultaneously with the application of fertilizers. Such practice prevents the rapid loss of the ammonium nitrogen added-as fertilizer and the ammonium nitrogen formed from the organic reduced nitrogen in fertilizers by the action of soil'bacteria. The administration to the soil of the triazole compound in an ammonium nitrogen fertilizer composition constitutes a preferred embodiment of the present invention.

The expression reduced nitrogen fertilizers is employed in the present. specification and claims, as understoodin the art, as embracing both inorganic and organic nitrogeneous materials "containing nitrogen in the reduced state. Examples of known reduced nitrogen fertilizers include anhydrous and aqueous ammonia, inorganic ammonium salts suchv as ammonium phosphate, ammonium nitrate and ammonium sulfate, ammonium salts of organic acids, urea, cyanamide, ,guanidine nitrate, dicyandiamide, amino acids, guanly urea sulfate, thiourea, uramon amines, urea-form and other nitrogen-containing organic chemical fertilizers as well as protein mixtures, animal tankages, green manure, fish products, crop residues, and other natural materials known to be sources of ammonium ionsin soil. These fertilizer materials contain nitrogenous compounds in which the apparent valency or oxidation state of the nitrogen is from minus 3 to minus 1, inelusive. Furthermore, inasmuch as the following equilibrium exists in the presence of water even when the latter is present in minor proportions,

it is to be understood that when reference is made herein to either ammonium ion or ammonia in soil it is meant to embrace the other component, namely, ammonia or ammonium ion, respectively.

The actual concentration of the triazole compound in compositions to be employed for the treatment of growth media is not critical and can vary considerably provided an effective, nitrification-inhibiting dosage of the triazole compound is supplied to the growth media. In general, good results are obtained with liquid compositions containing from about 0.0001 to about 0.25 percent by Weight of the triazole compound; in some operations, however, compositions containing amounts of triazole compound in excess of 0.25 percent, such asfrom 2 to 98 percent of triazole compound by weight of composition, are conveniently employed, as for example in row or band application. With dusts, good results are usually obtained with compositions containing from 0.001 to 10 percent or more by weight of triazole compound. In some circumstances, such as in high-intensity application, however, it is preferred to employ dust compositions containing as much as from v2 to 98 percent or more by weight of the triazole compound. Liquid or dust compositions in which the triazole compound is present in higher concentration can be utilized as such or can be employed as concentrate compositions to be diluted to prepare actual treating compositions.

Liquid compositions containing the desired amount of the triazole compound can be prepared by dispersing the latter in one or more liquid carriers such as water or an organic solvent, with or Without the aid of a suitable surface-active dispersing agent or emulsifying agent. Suitable organic solvents include, for example, diisobutylketone, methanol, ethanol, isopropyl alcohol, diethyl ether toluene, methylene chloride, chlorobenzene and the petroleum distillates. The preferred organic solvents are those which are of such volatility that they leave little permanent residue in the growth media. When the solutions of the triazole compound in organic solvents are to be further diluted to produce aqueous dispersions, the preferred solvents include acetone and the alcohols. When the liquid carrier is entirely organic in nature, particularly desirable carriers are the petroleum distillates boiling almost entirely under 400, F. at atmospheric pressure and.

having a flashpoint above about F. Dispersing and emulsifying agents which can be employed in liquid compositions include condensation products of alkylene oxides with phenols and organic acids, alkyl aryl sulfonates,

polyoxyalkylene derivatives of. sorbitan esters, complex ether alcohols, mahogany soaps and the like. The surfaceactive agents are generally employed in the amount of from 1 to 20 percent by Weight of the triazole compound. Solid compositions containing the active agent can be prepared by dispersing the latter in finely divided inert solid carriers such as sugar, salt, talc, chalk, gypsum, vermiculite and the like. Similarly, dust compositions containing the active compounds are prepared from various of the solid, surface-active dispersing agents such as fullers earth, attapulgite and other clays, as well as from solid fertilizer compositions. In preparing such compositions, the carrier is mechanically ground with the triazole compound or wet with a solutionor dispersion thereof in a volatile organic solvent. These solid compositions may, if desired, also contain an alkyl aryl sulfonate or other surface-active dispersing agent. Depending upon the proportions of ingredients, these compositions can be employed Without further modification or be considered as concentrates and subsequently further diluted with solid surface-active dispersing agent, talc, chalk, gypsum, or the like to obtain the desired treating composition. Furthermore, such concentrate compositions can be dispersed in water with or without added dispersing agent or agents to prepare aqueous soil treating compositions.

Soil treatment compositions can be prepared by dispersing the triazole compound in fertilizers such as ammonium fertilizer or organic nitrogen fertilizer. The resulting fertilizer composition can be employed as such and administered to the growth medium. Fertilizer compositions comprising the triazole compound in intimate admixture with ammonium fertilizers constitute preferred embodiments of the present invention.

In fertilizer compositions comprising a reduced nitrogen fertilizer, it is desirable that the triazole compound be present in an amount of at least about 0.25 percent by weight based on the weight of the nitrogen present in the fertilizer as reduced nitrogen, and the triazole compound can be present in amounts as high as 95 percent by Weight of the reduced nitrogen in the fertilizer. Generally, though, amounts of triazole compound in excess of about 25 percent yield no greater advantage and are therefore seldom used. Thus, when a fertilizer composition contains both reduced nitrogen and other forms of nitrogen, such as in the case of ammonium nitrate fertilizer compositions, the amount of triazole compound is based on the Weight of nitrogen present in the ammonium component.

In operations carried out in accordance with the present invention, as indicated hereinbefore, the soil can be impregnated in any convenient fashion with the active triazole compound or a composition containing the latter. For example, these modified or unmodified compositions can be mechanically mixed with the soil; applied to the surface of soil and thereafter dragged or disked into the soil to a desired depth; or transported into the soil with a liquid carrier such as by injection, spraying or irrigation. When the distribution is carried out by introducing the triazole compound in the water employed to irrigate the soil, the amount of water is varied in accordance with the moisture content of the soil in order to obtain a distribution of the triazole compound to the desired depth. The triazole compound can be readily and conveniently distributed to a depth of a few inches to four feet by irrigation methods. The preferred methods embrace procedures using any of these steps or combination of steps wherein triazole compound is distributed in the soil substantially simultaneously with a reduced nitrogen fertilizer.

By a practice of this invention, the nitrification of ammonium nitrogen in the soil to nitrate nitrogen is suppressed, thereby preventing the rapid loss of ammonium nitrogen from the soil. Furthermore, by proper distribution of the triazole compound, this action of inhibiting the transformation of ammonium nitrogen to nitrate nitrogen is effective over a prolonged period of time. The ammonium nitrogen may arise from added ammonium nitrogen fertilizers or be formed in the soil by conversion of the organic nitrogen constituents found in soil or added thereto as components of organic fertilizers.

The following examples illustrate the invention but are not to be construed as limiting.

EXAMPLE 1 In a representative operation, aqueous compositions each containing one of 4-amino-4H-1,2,4-triazole or 3,4- diamino-4H-1,2,4-triazole and an ammonium fertilizer are prepared by separately dissolving one of the triazole compounds in acetone and diluting the actone solution with an aqueous solution of ammonium sulfate. The compositions thus prepared each contain 500 p.p.m. of nitrogen and 25 p.p.m. of one of said triazole compounds. The amount of nitrogen expressed in this and other examples is based on the nitrogen present in the fertilizer in reduced form.

The aqueous compositions so prepared are employed to treat seed beds of sandy loam soil having a pH of about 8 containing essentially no organic matter and having been freed of nitrite and nitrate nitrogen by prior thorough leaching. In the treating operation, the seed beds are air dried and the compositions are applied to the dried seed beds as a soil drench in an amount suflicient to provide one of the triazole compounds at a concentration of p.p.m. together with a known amount of ammonium sulfate suflicient to provide approximately 100 p.p.m. of

nitrogen. A similar seed bed is treated in the same manner With an aqueous composition containing the same amount of ammonium sulfate and acetone, but no triazole compound, to serve as a check. The seed beds are sealed to prevent moisture loss and incubated at about 70 F. for two Weeks. At the end of this test period, the seals are removed and the soil in the seed beds is analyzed for combined nitrite plus nitrate nitrogen. The determinations are carried out by :xtracting the nitrate and nitrite from the soil with a saturated calcium sulfate solution, developing color in the clear supernatant of the extract with diphenylamine in sulfuric acid, and comparing the color with a standard solution containing known concentrations of nitrate and nitrite ions. This procedure is similar to that described in Colorimetric Methods of Analysis, by F. D. Snell and C. T. Snell, D. Van Nostrand Company, Inc., volume '11, 3rd edition, p. 801.

The soil in the check seed bed is found to contain 100 p.p.m. of combined nitrite and nitrate nitrogen. On the other hand, the soil in the seed beds treated with a triazole contains but a small percentage of this amount. Thus, in

the case of 4-amino-4H-1,2,4-triazole, the combined,

nitrate and nitrite content of the soil is 10 p.p.m., while with the 3,4-diarnino-4I-I-1,2,4-triazole the amount is 15 p.p.m.

EXAMPLE 2 In similar operations, aqueous reduced nitrogen fertilizers containing 10 p.p.m. of 4-amino4H-l,2,4-triazole and 1000 p.p.m. nitrogen are prepared by dispersing an 0.8 percent (weight by volume of solvent) acetone solution of the triazole compound in an aqueous ammonium sulfate solution.

A seed bed of alkaline sandy loam soil containing negligible amounts of ammonium nitrogen is then treated with the ammonium sulfate fertilizer composition, using the soil drench method, in an amount sutficient to provide 2 p.p.m. of the triazole compound. A similar seed bed is treated in this same manner with an aqueous ammonium sulfate solution containing acetone, but no triazole compound, to serve as a check. Both the test seed bed and the check bed initially contain about 200 p.p.m. of ammonium nitrogen. The seed beds are sealed and incubated for 4 weeks at 70 F. The air over the seed beds is changed weekly.

At the end of the test period, the ammonium nitrogen content of the soil in each seed bed is determined by a procedure involving distillation of the ammonia from the soil in the presence of magnesium oxide, sorption of the ammonia by boric acid, and titration of the resulting solution with a standard solution of hydrogen chloride. This method of analysis is a slight modification of that described by Black on p. 1198 of Methods of Soils Analysis, No. 2, American Society of Agronomy, Inc., Madison, Wis., 1965. The soil in the check seed bed is found to have undergone substantially complete nitrification and no detectable ammonia is recovered therefrom. In contrast, the soil in the seed bed treated with a triazole compound undergoes little if any nitrification. Specifically, the degree of nitrification with 4-amino-4-H-1,2,4-triazole is 15 percent. Expressed otherwise, of the nitrogen added as ammonium sulfate there is recovered percent.

EXAMPLE 3 Following a procedure similar to that of Example 2, aqueous reduced nitrogen fertilizers containing ammonium sulfate and one of 4-amino-4H-1,2,4-triazole:hydrochloride, 4-amino-4H-1,2,4-triazolezsulfate, 4-amino-4H- 1 ,2,4-triazole :phosphate, 4-amino-4H-1,2,4-triazoleznitrate, 3,4-diamino-4H-1,2,4-triazole:phosphate, 3,4-diamino-4H-1,2,4-triazolezsulfate and 3,4-diamino-4H-1,2,4-triazole:hydrobromide EXAMPLE 4 The operationv of this example is conducted with 3,4- diamino-4H-1,2,4-triazole. The test procedure used is one wherein soil-treating compositions are prepared by first dissolving the triazole compound in acetone at a concentration of 4 percent on a weight per volume basis. A fertilizer component is prepared by mixing 0.05 percent of an emulsifying agent (polyethylene glycol 600 oleate) in aqua ammonia containing 21 to 23 percent nitrogen. The solution of the triazole compound and the fertilizer are then mixed together so as to provide a composition containing 2 percent by weight of the triazole compound in terms of the weight of nitrogen present in the composition. Seed beds of a sandy loam soil having a pH of 8 and a 12 percent mositure content are treated with the above described composition. This treatment is carried out in such a fashion as to provide the seed bed with a concen tration of 125 p.p.mrby weight of nitrogen, the composition-being injected into the seed bed at a point about 3 inches below the soil surface. Otherseed beds having the same characteristics are treated with a composition differing from the foregoing only in the absence of the triazole compound, to serve as a check. Following the treatment, all seed beds are sealed to prevent loss of moisture and the soil is maintained at 70 F. for 30 days. At the end of this time, the treated and the check seed beds are analyzed for ammonium nitrogen in accordance with the same procedure as described above in Example 2. The seed bed treated with the triazole is found to contain 60 p.p.m. of ammonia nitrogen, while the check seed bed contains no ammonia nitrogen.

EXAMPLE The operation of this example is conducted with 3,4- diamino 4H 1,2,4 triazole..The test procedure is one wherein a nitrification inhibitor component is prepared by (a) mixing and grinding together 0.1 gram of the triazole compound and 0.15 gram of attapulgite, (b) adding 0.75 gram of pyrophyllite thereto and grinding the resulting mixture until a finely powdered uniform composition is obtained. A fertilizer component is prepared by hammermilling together a 50:50 mixture by weight of ammonium sulfate and pyrophyllite to obtain a fine uniform composition. The inhibitor component and fertilizer compo.- nent are mixed together on a roller mill to obtain soiltreating compositions containing a triazole compound in varying concentrations expressed as percent based on the weight of nitrogen in the composition, these varying concentrations being 2, 1, 0.5 and 0.25 percent. These compositions are employed to fertilize" various beds of sandy loam soil containing very little organic material, having a pH of about 8, and having a moisture content of about 20 percent. The beds are in containers which admit of being sealed to prevent loss of moisture. The seed beds are fertilized in areas to be planted by providing depressions and adding thereto'the fertilizer treating composition and then covering the composition with soil. The amount of composition employed is sufiicient to supply 206 parts by weight of nitrogen and, variously, 4, 2, 1 and 0.5 parts by weight of each triazole compound, per million parts by weight of soil. Thereupon, the seed beds are sealed to prevent loss. of moisture and the soil maintained at temperatures of about 70 F. for 5 weeks. At 7 day intervals, the seals are removed, air passed over the soil, andthe seals then replaced. At the end of the 5 Week period, the seals are finally removed and samples of soil are analyzed, as described in Example 2, for ammonium nitrogen content. The results are compared with check seed beds wherein no triazole compound is added to the fertilizer composition, but which are otherwise identically handled. The results obtained are as reported below:

Triazol compound (p.p.m.

parts by wt. of soil) 3,4-diamino-4H-1,2,4-triazole:

1 Parts by wt.

0.5 94 None (check) 0 dtlAdmmonium nitrogen recovered from 206 parts by weight a e EXAMPLE 6 700) are mechanically mixed together to obtain a waterdispersible mixture.

A composition of each of the two'foregoing types is similarly prepared with each of the other triazole compounds recited in Example 3.

The foregoing compositions can be dispersed in water to produce aqueous compositions having desirable wetting and penetrating properties. These aqueous compositions are then employed to treat soil in an amount sufiicient to distribute the triazole therein in effective nitrification,

inhibiting concentrations. The concentrates can also be dispersed in aqueous ammonia to prepare reduced nitrogen fertilizer compositions.

EXAMPLE 7 Fertilizer compositions are prepared as follows: (A) 4 amino-4H-l,2,4-triazole:phosphate is mechanically mixed with diammonium phosphate to prepare a re-,

duced nitrogen fertilizer composition containing 5 percent by weight of the triazole compound.

(B) 3,4 diamino-4H-1,2,4-triazoleznitrate is mechanically mixed with ammonium nitrate to prepare a reduced nitrogen fertilizer composition containing 3 percent by weight of the triazole compound.

(C) 3,4 diamino-4H-1,2,4 triazole is mechanically mixed with urea to prepare a reduced nitrogen fertilizer composition containing 2 percent by weight of the triazole compound.

A composition of each of these three types is similarly prepared with each of the other triazole compounds set forth in Example 3.

These fertilizer compositions are distributed in soil to supply the nitrogen requirements for plant nutrition. The treated soil is resistant to nitrification and provides nitrogen available for plant growth over a prolonged period of time.

EXAMPLE 8 A solid fertilizer composition is prepared as follows: (1) a nitrification inhibitor component is prepared by mixing together 5 parts by weight of 3,4 diamino-4H-1,2,4- triazolezsulfate with 1.5 parts of attapulgite clay and then adding 7.5 parts of pyrophyllite thereto and grinding the tion; and (3) the inhibitor and fertilizer components are mixed together on a rolling mill in varying proportions so as to obtain soil treating compositions containing the triazole in concentrations of 0.5, 1 and 2 percent based on the weight of nitrogen in the composition.

The 4-amino-4H-1,2,4-triazole employed in a practice of this invention is prepared in a known manner by heating formylhydrazide at atmospheric pressure to 200 C. for 3 hours thereby effecting condensation of the starting material. The 3,4-diamino-4H-1,2,4-triazole employed in the present invention may be prepared in accordance with the method described by Gaiter, Gazz. Chim. Ital., 451, p. 457, whereby diamino guanidine hydrobromide is heated with an approximately equimolar amount of formic acid on a steam bath, and thereafter removing the HBr component of the resulting 3,4 diamino-4H-1,2,4- triazole hydrobromide salt by treatment with moist silver oxide.

The mineral acid addition salts to be employed in accordance with the present invention are prepared in standard procedures, in which the triazole compound is reacted with the desired mineral acid. The reaction is carried out in a liquid reaction medium and the reactants are employed in amounts representing stoichiometric proportions. The reaction goes forward readily at room temperatures with the preparation of the desired salt product, which typically appears in the liquid reaction mixture as a crystalline solid. The product, a solid, is separated by filtration or decantation, or the liquid reaction mixture can be removed by evaporation to separate the product. The salt products are generally of low solubility in organic liquids and of moderate solubility in water.

When it is desired that one of the salt products of the present invention be applied to soil simultaneously with the application of a nitrogen fertilizer, it is often preferred that the specific salt product be prepared in conjunction with the preparation of the nitrogen fertilizer. Representative nitrogen fertilizers for which such procedures are particularly appropriate are ammonium phosphate, ammonium sulfate, ammonium nitate and ammonium chloride. In these procedures, the triazole compound is' reacted with the given mineral acid simultane- 1O ously with its reaction to form the respective nitrogen fertilizer. The resulting product comprises the given nitrogen fertilizer or fertilizers and the corresponding triazole compound in salt form and is advantageously employed in the practice of the present invention.

I claim:

1. A method comprising distributing in a plant growth medium a nitrification-inhibiting amount of 4-amino-4H- 1,2,4-triazole, 3,4-diamino-4H-1,2,4-triazole or a mineral acid addition salt formed by reacting one or the other of said triazole compounds with an acid selected from the group consisting of hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, nitric acid and phosphoric acid.

2. A composition comprising a reduced nitrogen fertilizer as a source of ammonium ions in admixture with a nitrification-inhibiting amount of 4 amino 4H-1,2,4-triazole, 3,4-diamino-4H-1,2,4-triazole or a mineral acid ad- 'dition salt formed by reacting one or the other of said UNITED STATES PATENTS 2/1966 Harrison 71-1 REUBEN FRIEDMAN, Primary Examiner R. BARNES, Assistant Examiner US. Cl. X.R. 7127 

